1. Field of the Invention
The present invention relates in general to data processing and in particular, to methods for dual processor audio decoder and methods with sustained data pipelining during error conditions.
2. Description of the Related Art
The ability to process audio information has become increasingly important in the personal computer (PC) environment. Among other things, audio support is important requirement for many multimedia applications, such as gaming and telecommunications. Audio functionality is therefore typically available on most conventional PCs, either in the form of an add-on audio board or as a standard feature provided on the motherboard itself. In fact, PC users increasingly expect not only audio functionality but high quality sound capability. Additionally, digital audio plays a significant role outside the traditional PC realm, such as in compact disk players, VCRs and televisions. As the audio technology progresses, digital applications are becoming increasingly sophisticated as improvements in sound quality and sound effects are sought.
One of the key components in many digital audio information processing systems is the decoder. Generally, the decoder receives data in a compressed form and converts that data into a decompressed digital form. The decompressed digital data is then passed on for further processing, such as filtering, expansion or mixing, conversion into analog form, and eventually conversion into audible tones. In other words the decoder must provide the proper hardware and software interfaces to communicate with the possible compressed (and decompressed) data sources, as well as the destination digital and/or audio devices. In addition, the decoder must have the proper interfaces required for overall control and debugging by a host microprocessor or microcontroller. Since, there are a number of different audio compression/decompression formats and interface definitions, such as Dolby AC-3 and S/PDIF (Sony/Phillips Digital Interface), a state of the art digital audio decoder should at least be capable of supporting multiple compression/decompression formats.
In almost any processing system operating on streams of data, especially encoded data, error handling is a key issue. For the exemplary case of an audio decoder, unless errors received in the input data stream are accounted for, the processed data output to the digital to analog converters will be corrupted. Ultimately, the corrupted data will manifest themselves, after mixing and digital to analog conversion, to the end user as audible distortions, clicks, pops, etc. Therefore, as processing systems advance in capability and complexity, new and more efficient methods of error handling are required.